This invention relates to a thermal printer and a cassette therefor.
A thermal printer is one in which printing is carried out using an electrically activated print head with a plurality of individually energisable heating elements which, when brought into contact with an ink ribbon and heated, transfer the ink from the ribbon to an image receiving tape in accordance with the data to be printed. A cassette carrying the ink ribbon and the image receiving tape is loaded into the printer so that the ink ribbon and image receiving tape are guided in overlap through a printing zone. During printing, the image receiving tape is held against the ink ribbon by a platen bearing against the print head and holding the ink ribbon and image receiving tape under pressure therebetween.
A thermal printer of this type is described in European Patent Application No. 0322919 in the name of Brother.
In this thermal printer, the printing zone is defined by a print head which is fixedly mounted in the printer and a platen which is moveable between a printing state in which the platen bears against the print head and an inoperative state in which the platen is spaced from the print head to define a gap to enable a cassette to be inserted with the image receiving tape and ink ribbon in overlap in the gap. The platen is mounted on a holder member which can be moved by a lever between the two states. The cassette for the thermal printer houses, in addition to the ink ribbon and image receiving tape, a spool carrying an adhesive backing layer which is applied to the printed surface of the image receiving tape after it has been printed and before it is fed out of the printer. This is accomplished by cooperation of a feed roller of the cassette and a drive roller mounted on the holder member. When the holder member is moved to bring the platen into its printing state the drive roller is brought into contact with the feed roller to form a nip to drive the printed tape from the printer which applied the adhesive backing layer.
One problem with this printer is the need to move the platen from its operative to its inoperative position by means of a manually operable lever before removing a cassette from the printer to replace it. If a user forgets to do this, and attempts to remove a cassette while the platen is in the printed state, damage to the printer and/or cassette is likely to result.
Furthermore, with the known printer, the cassette is loaded from underneath the printer, which can be inconvenient for a user.